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Jan T. Sobczyk

Publications and source records attributed to Jan T. Sobczyk.

48 records · Page 3Linked to original sources

Appearance of quark-hadron duality in the Rein-Sehgal model

Quark-hadron duality in neutrino-nucleon reactions is investigated under the assumption that cross sections in the resonance region are given by the Rein-Sehgal model. The quantitative analysis of the duality is done by means of appropriate integrals of the structure functions in the Nachtmann variable. We conclude that with the definition of the resonance region $W\in (M+m_π, 2$ GeV) the duality holds for neutrino-proton reaction $F_2$ structure function for $Q^2\in (0.5, 3)$ GeV$^2$ and it is absent for neutrino-neutron reaction.

hep-ph↗

Simulations from a new neutrino event generator

We construct a new Monte Carlo generator of events for neutrino interactions. The dynamical models for quasi-elastic reactions, $Δ$ excitation and more inelastic events described by the DIS formalism with the PDFs modified according to recent JLab data are used. We describe in detail single pion production channels, which combine the $Δ$ excitation and DIS contribution. Many comparisons of the outcome of simulations with experimental data are presented.

hep-ph↗

Spectrum of outgoing nucleons in quasielastic neutrino-nucleus interactions

We have analyzed the consequences of introducing the local density approximation combined with an effective nuclear momentum-dependent potential into the CC quasi-elastic neutrino-nucleus scattering. We note that the distribution of the recoil nucleons momenta becomes smooth for low momentum values and the sharp threshold is removed. Our results may be relevant for Sci-Fi detector analysis of K2K experiments. The total amount of observed recoil protons is reduced because some of them remain bound inside the nucleus. We compare theoretical predictions for a probability of such events with the results given by NUX+FLUKA MC simulations.

nucl-th↗

WroNG -- Wroclaw Neutrino Generator of events for single pion production

We constructed a new Monte Carlo generator of events for neutrino CC single pion production on free nucleon targets. The code uses dynamical models of the DIS with the PDFs modified according to the recent JLab data and of the Delta excitation. A comparison with experimental data was done in three channels for the total cross sections and for the distributions of events in invariant hadronic mass.

hep-ph↗

On two weak CC Delta production models

We perform a detail analysis of two models of neutrino CC Delta production on free nucleons. First model is a standard one based on nucleon-Delta transition current with several form-factors. Second model is a starting point for a construction of Marteau model with sophisticated analytical computations of nuclear effects. We conclude that both models lead to similar results.

hep-ph↗

Comparison of predictions for nuclear effects in the Marteau model with the NUX+FLUKA scheme

Nuclear effects in neutrino-nucleus reactions simulated by means of the NUX+FLUKA Monte Carlo generator are compared with the theoretical predictions of the Marteau model. Pion absorption in NUX+FLUKA and non-pionic Delta decays in the Marteau model differ by about 30%. The fraction of pions produced due to the re-interactions after primary quasi-elastic vertex is in the NUX+FLUKA scheme much higher then provided by the Marteau model.

nucl-th↗

New Quantum Deformation of Osp(1;2)

The complete set of formulas describing the new quantum deformation of the OSP(1;2) supergroup is provided. A general ansatz is solved for the deformation of the Borel subalgebra of its dual quantum deformation of osp(1;2).

math.QA↗

Classification of Low Dimensional Lie Super-Bialgebras

A thorough analysis of Lie super-bialgebra structures on Lie super-algebras osp(1|2) and super-e(2) is presented. Combined technique of computer algebraic computations and a subsequent identification of equivalent structures is applied. In all the cases Poisson-Lie brackets on supergroups are found. Possibility of quantizing them in order to obtain quantum groups is discussed. It turns out to be straightforward for all but one structures for super-E(2) group.

q-alg↗

Operator Formalism for Bosonic Beta-Gamma Fields on General Algebraic Curves

An operator formalism for bosonic $β-γ$ systems on arbitrary algebraic curves is introduced. The classical degrees of freedom are identified and their commutation relations are postulated. The explicit realization of the algebra formed by the fields is given in a Hilbert space equipped with a bilinear form. The construction is based on the "gaussian" representation for $β-γ$ systems on the complex sphere [Alvarez-Gaum\' e et al, Nucl. Phys. B 311 (1988) 333]. Detailed computations are provided for the two and four points correlation functions.

hep-th↗

Monodromy Properties of the Energy Momentum Tensor on General Algebraic Curves

A new approach to analyze the properties of the energy-momentum tensor $T(z)$ of conformal field theories on generic Riemann surfaces (RS) is proposed. $T(z)$ is decomposed into $N$ components with different monodromy properties, where $N$ is the number of branches in the realization of RS as branch covering over the complex sphere. This decomposition gives rise to new infinite dimensional Lie algebra which can be viewed as a generalization of Virasoro algebra containing information about the global properties of the underlying RS. In the simplest case of hyperelliptic curves the structure of the algebra is calculated in two ways and its central extension is explicitly given. The algebra possess an interesting symmetry with a clear interpretation in the framework of the radial quantization of CFT's with multivalued fields on the complex sphere.

hep-th↗